The present invention relates to a semiconductor device and concerns a technology applicable to the semiconductor device, for example, having a structure that an impurity has been implanted into a side face of a trench formed in a substrate.
In the semiconductor device, there are cases when the trench is formed in the substrate and an impurity region that extends in a depth direction in the substrate is formed by diagonally implanting the impurity into the trench. Japanese Unexamined Patent Application Publication No. 2002-118256 describes that a low concentration impurity layer is epitaxially grown on a high concentration impurity substrate, the trench that reaches the high concentration impurity substrate is formed in the low concentration impurity layer and the impurity is diagonally implanted into the trench. In this case, an n-type impurity region is formed on one side face of the trench and a p-type impurity region is formed on the opposite side face of the trench by implanting ions of an n-type impurity from a first direction and implanting ions of a p-type impurity from the side opposite to the first direction.
On the other hand, Japanese Unexamined Patent Application Publication No. 2011-66067 describes that element isolation is performed by forming a groove so as to surround an element in a substrate with elements such as a transistor and so forth formed and burying an insulating film into the groove. In Japanese Unexamined Patent Application Publication No. 2011-66067, an element isolation film of an STI structure is formed in addition to this groove. The above-mentioned groove is formed deeper than the element isolation film.